Optical sensing technologies are among the most versatile hardware solutions for interactive surfaces, as they are capable of recognizing touch as well as (limited) hover state in addition to printed tokens. One widely used system is the Pixelsense/SUR40, currently one of very few devices which provides these capabilities in the form factor of a regular table, thereby allowing working at the device in a sitting position. Unfortunately, the device has been discontinued by the manufacturer, provides only an unsupported SDK on an outdated operating system, and has a gathered a reputation for high latency as well as sensitivity to environment light. In this paper, we present our research into modernizing and extending the SUR40 system. By switching to a Linux operating system running a custom video driver, we are able to provide lower latency, support other types of optical tags and improve the system's robustness, particularly regarding external lighting conditions. We present an analysis of the device's internals, a comparison of quantitative performance measurements, and an outlook into extending the tangible interaction capabilities with an improved cross-platform development framework.

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